Good Evidence of Benefits From Ketosis Part 4

Published by joseph on

Obviously exercise isn’t a disease, but it’s included here because some exciting things are happening for athletes who eat a low-carb, moderate-protein, high-fat, ketogenic diet. Dr. Stephen Phinney, the ketogenic diet researcher we have referenced often throughout this book, was one of the first to study the impact of ketosis on exercise performance way back in 1983. His landmark study, published in the August 1983 issue of the journal Metabolism, looked at how a ketogenic diet affected the endurance training of five elite cyclists.

After four weeks of eating ketogenic, with less than 20 daily grams of carbohydrate in their diet, the athletes did not see their performance compromised by being in ketosis because they had shifted from sugar-burners to fat-burners. Although their glycogen stores at the end of the four weeks were considerably lower than at baseline, not only did they not crash from hypoglycemia, they actually improved their overall output.

This is when Dr. Phinney coined the phrase nutritional ketosis to describe the state in which someone is keto-adapted. For these elite athletes, their fuel source had shifted fully from carbohydrates (glucose) to fat and ketones.

A strategic use of ketosis has been the only way I’ve been able to stay lean without a lot of effort, and this holds true for my clients as well. For athletes, it’s the only method available for losing extreme amounts of body fat while maintaining, or even increasing, performance.

– John Kiefer

The 1983 study was almost ended prematurely. The cyclists’ response to the diet in the first couple of weeks resulted in a decline in performance, and the researchers thought the nutritional changes were proving to be more detrimental than helpful. But Dr. Phinney fortuitously decided to press on for at least one more week. That’s when keto-adaptation happened, and the improvements in key data points such as oxygen utilization (VO2 max), respiratory quotient, amount of glycogen in the muscle, and more all began to manifest. Can you imagine how that study would have turned out if they stopped after only two weeks?

Dr. Phinney notes the importance of this period of adaptation in an August 27, 2004, paper entitled “Ketogenic Diet and Physical Performance” published in the journal Nutrition & Metabolism. You can Google the title of this paper to read it for yourself; it complements everything we’ve been sharing with you in this book. Additionally, Dr. Phinney, along with his research partner Dr. Jeff Volek, cowrote a book in 2012 that chronicles a lot more about this information and what they’ve learned using a low-carb, high-fat approach with athletes called The Art and Science of Low Carbohydrate Performance.

Although the research on athletics and ketogenic diets is still emerging (another study featuring elite gymnasts was published in the Journal of the International Society of Sports Nutrition in 2012), many elite athletes are willingly and openly trying it for themselves with great success. One such endurance athlete is Timothy Allen Olson, an Oregon-based long-distance runner who ran in the 2012 Western States 100-Mile Endurance Run to show the world what a ketogenic runner could do. Did he win the race? You bet he did, and his time was twenty-one minutes faster than the previous course record!

Ben Greenfield is a triathlete who followed a strict ketogenic diet for sixteen weeks during his training for the Ironman Canada and Ironman Hawaii races in 2013. He consumed far fewer carbohydrates (less than 200 grams) than the typical Ironman triathlete would—they often consume 600 to 800 grams of carbohydrate on a training day—and supplemented with coconut oil and MCT oil to help his body shift to using fat for fuel. Here are the major benefits Greenfield found from being in ketosis:

  • Increased metabolic efficiency and enhanced fat burning, which lets him “get stronger as the day gets longer.” This is especially useful for endurance athletes, such as those participating in Ironman competitions and long-distance marathons.
  • Sparing of glycogen stores, which also leads to increased endurance. He uses less stored muscle and liver carbohydrates because he’s able to burn fat more efficiently.
  • Lowered inflammation, which enables his body to recover faster after a workout due to the decreased formation of free radicals and reactive oxygen species (molecules that can damage cells) from a high amount of sugar intake.
  • More stable energy levels because his blood sugar levels don’t fluctuate as they would on a carbohydrate-based diet.


Ketone bodies have become known as a superfuel because they provide more energy per unit of oxygen than other metabolic fuels. This improved metabolic efficiency was first shown in sperm cells, in which exposure to ketone bodies decreased oxygen consumption while increasing mobility. This was later confirmed in a study that showed ketone bodies increased the heart’s hydraulic work capacity while simultaneously decreasing oxygen consumption. This may explain why there is a flourishing community of keto-adapted athletes that is rapidly increasing.

– Dr. Bill Lagakos

And, finally, there’s Olaf Sorenson, a forty-year old long-distance runner who is putting the idea of getting into ketosis for athletic performance to the test himself. At the time of writing, he is documenting his low-carb, high-fat experience in a movie tentatively called Two Forty, Forty One, a reference to his stated goal to run the marathon in less than two hours, forty minutes, and forty-one seconds.

Why is this time so significant? In 1952, Sorenson’s grandfather qualified for the Olympics with that time. Now he’s attempting to match it while in ketosis from consuming a lots of healthy saturated fats and ditching carbohydrates. Sorenson’s progress and state of health during his marathon training are being tracked by the College of Health and Human Performance at the University of Florida.

We’ve got some really good evidence in support of ketogenic diets that certainly could use more clinical, human research on a wider scale in the coming years. There are many more conditions that may improve on a low-carb, high-fat diet, but the evidence is less clear—we only have animal models or anecdotal stories in support of the theory. The therapeutic use of ketones for these conditions is an emerging area of research that should be much more closely examined in the coming years, and we’ll take a look at these health conditions in the next chapter.

Key Keto Clarity Concepts

  • We have good evidence, from studies less than a year in duration, that many conditions are improved by a ketogenic diet.
  • Alzheimer’s, Parkinson’s, and dementia are all shown to get better on a low-carb, moderate-protein, high-fat diet.
  • Schizophrenia, bipolar disorder, and other mental illnesses get better with ketones.
  • Narcolepsy and other sleep disorders show modest improvement in people in ketosis.
  • Better exercise performance is emerging as a huge benefit of eating a low-carb, high-fat diet.
Categories: Diet


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